Mesaverde Group sandstone units in 13 closely-spaced wells in the central and southern Piceance Basin of Colorado were correlated utilizing wireline log response quantitatively and qualitatively. Based on these correlations, the environmental subdivisions of the Mesaverde Group were characterized as follows: (1) paralic (upper mixed-marine) zone, occurring in the uppermost Mesaverde Group, includes thick sandstone units which are interpreted to be regionally continuous, (2) fluvial zone, containing point-bars 20 to 30+ ft thick, is interpreted to be correlatable to a maximum of 6800 ft, and (3) paludal zone has insufficient data to adequately characterize the sand units. However, 63 percent of the units are correlatable across at least 139 ft. An approximation of the dimensional characteristics of Mesaverde sandstone units has potential applications in designing hydraulic fracturing treatments and estimating gas reserves more accurately. 15 figures, 2 tables.

GEOTHERM sample file contains 225 records for Colorado. Three computer-generated indexes are found in appendices A, B, and C of this report. The indexes give one line summaries of each GEOTHERM record describing the chemistry of geothermal springs and wells in the sample file for Colorado. Each index is sorted by different variables to assist the user in locating geothermal records describing specific sites. Appendix A is sorted by the county name and the name of the source. Also given are latitude, longitude (both use decimal minutes), township, range, section, GEOTHERM record identifier, and temperature (/sup 0/C). Appendix B is sorted by county, township, range, and section. Also given are name of source, GEOTHERM record identifier, and temperature (/sup 0/C). Appendix C is first sorted into one-degree blocks by latitude, and longitude, and then by name of source. Adjacent one-degree blocks which are published as a 1:250,000 map are combined under the appropriate map name. Also given are GEOTHERM record identifier, and temperature (/sup 0/C). A bibliography is given in Appendix D.

A 7118 ft (2170 m) deep geothermal test well was drilled on the south edge of the city of Alamosa, Colorado as part of the Department of Energy's User Coupled Confirmation Drilling Program. The project was selected on the bases of a potential direct heat geothermal resource within the Rio Grande rift graben and resource users in Alamosa. The well site was selected on the hypothesis of a buried horst along which deep thermal fluids might be rising. In addition, there were city wells that were anomalous in temperature and the location was convenient to potential application. The Alamosa No. 1 penetrated 2000 ft (610 m) of fine clastic rocks over 4000 ft (1219 m) of volcaniclastic rock resting on precambrian crystalline rock at a depth of 6370 ft (1942 m). Due to poor hole conditions, geophysical logs were not run. The stabilized bottom hole temperature was 223/sup 0/F (106/sup 0/C) with a gradient of 2.6/sup 0/F/100 ft (47/sup 0/C/km). Limited testing indicated a very low production capacity. 16 refs., 6 figs.

Appendices containing data on uranium availability in the Cortez Quadrangle to accompany a report on U.S. uranium resources in Colorado and Utah.

Appendices containing data on uranium availability to accompany a report on U.S. uranium resources in the Craig Quadrangle, Colorado.

Appendices containing data on uranium availability in the Moab Quadrangle to accompany a report on U.S. uranium resources in Colorado and Utah.

Analysis of 21 post-burn cores taken from the Hanna IV UCG site allows 96 m (315 ft) of overburden to be subdivided into four local stratigraphic units. The 7.6 m (25 ft) thick Hanna No. 1 coal seam is overlain by a laterally discontinuous, 3.3 m (11 ft) thick shaley mudstone (Unit A') in part of the Hanna IV site. A more widespread, 30 m (90 ft) thick well-indurated sandstone (Unit A) overlies the A' unit. Unit A is the roof rock for both of the Hanna IV cavities. Overlying Unit A is a 33 m (108 ft) thick sequence of mudstone and claystone (Unit B), and the uppermost unit at the Hanna IV site (Unit C) is a coarse-grained sandstone that ranges in thickness from 40 to 67 m (131 to 220 ft). Two elliptical cavities were formed during the two phases of the Hanna IV experiment. The larger cavity, Hanna IVa, is 45 x 15 m in plan and has a maximum height of 18 m (59 ft) from the base of the coal seam to the top of the cavity; the Hanna IVb cavity is 40 x 15 m in plan and has a maximum height of …

Appendices containing data on uranium availability in the Shiprock Quadrangle to accompany a report on U.S. uranium resources in New Mexico, Arizona, Colorado, and Utah.

Appendices containing supplementary analytical data of uranium occurrences, chemical analyses of stream-sediment, rock, and soil samples, and tabulated radiometric and gamma-ray anomaly data to accompany a report on U.S uranium resources in the Leadville Quadrangle, Colorado.

A three-dimensional model was created to estimate vertical hydraulic conductivity and regional ground-water flow rates in rocks within the San Juan Basin in New Mexico and Colorado.

From abstract: Three closely spaced wells drilled through the Upper Cretaceous Mesaverde Group and were extensively cored and logged in order to identify the factors controlling the occurrence and distribution of gas in low-permeability rocks and to improve recovery technology.

In 1977 a program was initiated to delineate the geological features controlling the occurrence of geothermal resources in Colorado. This program consisted of literature search, reconnaissance geologic and hydrogeologic mapping and geophysical and geochemical surveys. During 1980 and 1981 geothermal resource assessment efforts were conducted in the Cement Creek Valley south of Crested Butte. In this valley are two warm springs, Cement Creek and Ranger, about 4 mi (6.4 km) apart. The temperature of both springs is 77 to 79/sup 0/F (25 to 26/sup 0/C) and the discharge ranges from 60 to 195 gallons per minute. Due to access problems no work was conducted in the Cement Creek Warm Springs area. At Ranger Warm Springs electrical resistivity and soil mercury surveys were conducted. The warm springs are located in the Elk Mountains of west central Colorado. The bedrock of the area consists of sedimentary rocks ranging in age from Precambrian to Recent. Several faults with displacements of up to 3000 ft (194 m) are found in the area. One of these faults passes close to the Ranger Warm Springs. The electrical resistivity survey indicated that the waters of Ranger Warm Springs are moving up along a buried fault which parallels …

A report with the purpose of developing a practical system for quantitatively assessing the uranium resources in individual quadrangles based upon the HSSR data and tonnage/grade data for occurrences.

From Introduction: "The Leadville Quadrangle, Colorado (Fig. 1), was evaluated to identify and delineate areas and geologic units that exhibit characteristics favorable for the occurrence of uranium deposits. Geologic environments were placed into one of three categories--favorable, unfavorable, or unevaluated--based on National Uranium Resource Evaluation (NURE) program."

From Introduction: "The Montana Quadrangle of the National Topographic Map Series (NTMS), scale 1:250,000, in west-central Colorado was evaluated for geologic environments favorable for uranium deposits."

From Introduction: "The Cortez 1º x 2º Quadrangle, southwestern Colorado and southeastern Utah (Fig. 1), was studied to identify and evaluate areas and geologic formations that are favorable for the occurrence of uranium deposits of specific minimum size and grade."

From Introduction: "The Moab 1ºX2º Quadrangle, east-central Utah and west-central Colorado (Fig. 1) was studied to identify and evaluate areas and geologic formations that are favorable for the occurrence of uranium deposits of specific minimum size and grade."

Abstract: Water shortages are expected in the Upper Colorado River Basin because of increasing water demands for various uses. Ground-water supplies can help to reduce water shortages but ground-water reservoirs have not been studied in detail. The regional aquifer systems analysis of the Upper Colorado River Basin is a study of the major ground-water resources of the region. Aquifers occur in the sedimentary rock sequences in basins and uplifted regions, in volcanic-rock regions, and in stream-valley alluvium. The project work will include collection and compilation of existing geologic, geophysical, hydrologic, and geochemical data. These data will be used to assess the hydrologic characteristics of the aquifer systems and to estimate the hydrologic effects of discharge from, or recharge to, selected aquifers.

From Introduction: "The La Junta Quadrangle, Colorado and Kansas (Fig. 1), was evaluated to identify and delineate areas and geologic units to a depth of 1500 m (5,000 ft) that exhibit characteristics favorable for the occurrence of uranium deposits, which could contain at least 100 tons U3O8 and have an average grade of not less than 100 ppm U3O8."

From purpose and study: The Durango Quadrangle, southwest Colorado (Fig. 1), was evaluated to identify geologic units and to delineate areas that exhibit characteristics favorable for uranium deposits. Geologic environments were evaluated to a depth of 1500 m based on recognition criteria (Mickle and Mathews, eds., 1978) prepared for the National Uranium Resource Evaluation (NURE) program. A favorable environment, as defined for this program, is an environment that could contain at least 100 tons U308 in deposits with an average grade no less than 100 ppm U308 . Environments that did not meet the NURE criteria were categorized as unfavorable. Some of the subsurface and several areas of restricted access were categorized as unevaluated because insufficient data exist for proper evaluation.

From Introduction: "The purpose of the National Uranium Resource Evaluation (NURE) program of the U.S. Department of Energy (DOE) is to identify and delineate areas and environments with the Shiprock 1ºx2º Quadrangle, New Mex., Ariz., Colo., and Utah, that exhibit characteristics favorable for the occurrence of uranium deposits that have potential to contain at least 100 metric tons U3O8 total endowment with an average minimum grade of 100 ppm (0.01 percent)."

From abstract: This report uses chemical and bacteriological data to "describe the quality of water from selected geologic units in Routt County, Colorado.

From purpose and scope: The purpose of the National Uranium Resource Evaluation (NURE) program of the U.S. Department of Energy (DOE) is to identify and delineate areas and environments within the Aztec 10X20 Quadrangle, New Mexico and Colorado, that exhibit characteristics favorable for the occurrence of uranium deposits that have the potential to contain at least 100 metric tons U3 08 total endowment with a minimum grade of 100 ppm (0.01 percent) U3 08 . Evaluation is based on geochemical, mineralogic, hydrologic, aerial radiometric, sedimentologic, and general geologic characteristics of the formations in the quadrangle.

Results of reconnaissance surveys of the Denver quadrangle to determine the likelihood of uranium deposits of the area, and additional information about the location and classification of any deposits.